See the first-ever survey of the Atascosa Highlands

An ecologist and a photographer teamed to document and build a living archive of the Borderlands’ biodiversity — before it’s too late.

For a few weeks in April and May, the elegant trogon (Trogon elegans) breeds in the rugged Atascosa Highlands that straddle the Arizona-Mexico border, flashes of its brilliant crimson belly occasionally visible among the sycamore trees. The birds are migrants, and have long pushed north from a historic range that extends through Mexico as far south as Costa Rica to breed in the highlands. Increasingly, driven by climate change, habitat loss and wildfire, the trogons are spending longer periods of time in this cooler land. 

Trogons are one of the many rare birds found in the four small mountain ranges that make up the highlands at the junction of the Sonoran and Chihuahuan deserts. Some of the peaks rise 6,000 feet above the surrounding desert, creating their own ecosystems, each so distinct and biologically diverse that they are known as “sky islands.”


Detail of Opuntia santa-rita (Santa Rita prickly pear) (top), Graptopetalum bartramii (Patagonia leather petal).
The Atascosa Highlands are the homeland of the Tohono O’odham and Hohokam people, and the area is full of the remnants of human history: the Indigenous stewards whose controlled burns encouraged an even  greater variety of vegetation; the 19th century miners who scoured Walker Canyon for silver; the buffalo soldiers of the 10th Cavalry who served as border guards during World War I. The land is scarred by the infrastructure of an arbitrary border, with razor-wire fences and forbidding walls, and it continues to be threatened by border construction. But people still move across the landscape, sharing their stories and lives, engaging in commerce along International Avenue in the border-straddling city of Nogales, which hugs the Highlands’ southeastern edge.


Each so distinct and biologically diverse that they are known as “sky islands.”

Sycamore Canyon.

This part of the Borderlands has been widely examined through the lens of politics and human migration but scarcely considered on its own terms. Yet it is an ecological utopia, a place of rich biodiversity and myriad communities of wrens, warblers and trogons, oak groves and acacia, javelina and mountain lions, prickly pear and piñon.

The images presented here are part of an ongoing project by ecologist Jack Dash and photographer Luke Swenson, who are creating the first - and so far, only - comprehensive botanical survey of the Atascosa Highlands. As Dash and Swenson started to document the highlands’ natural environment, they realized they couldn’t address the landscape without acknowledging the impact humans have had on it - and continue to have, through large-scale projects and the impacts of climate change. They discovered that there is no dividing line between history and natural history. With the Atascosa Highlands hosting roughly half of Arizona’s bird species and one-quarter of its flora, including several species that are not known to exist anywhere else in the United States, the project has become both an elegy and a baseline, a chronicle of the region at this particular moment in time, and a way to acknowledge what is there before it is gone. —Paige Blankenbuehler

Scrub grassland and oak woodland ecotone.

Carex chihuahuensis (Chihuahuan sedge).
Clockwise from top left, Baccharis sarothroides (desert broom), Lobelia laxiflora (Sierra Madre lobelia), Agave palmeri (Palmer’s agave), Cirsium arizonicum (Arizona thistle).
This part of the Borderlands has been widely examined through the lens of politics and human migration, but scarcely considered on its own terms. 

Center, Mimosa dysocarpa (velvetpod mimosa). Clockwise from top left, Opuntia engelmannii (Engelmann’s prickly pear), Noccaea fendleri (alpine pennycress), Delphinium scaposum (barestem larkspur), Juniperus arizonica (Arizona juniper), Tillandsia recurvata (ball moss), Elionurus barbiculmis (woolly balsamscale), Stachys coccinea (scarlet betony), Mentzelia montana (blazing star).
Border wall construction is visible from Cumero Mountain, Atascosa Mountains, Arizona.
Canyon scrub (left), Buddleja sessiliflora (butterfly bush) (right).
Tailings from the now-defunct Ruby Mine.

Atascosa Borderlands, a visual storytelling project about a remote stretch of the U.S.-Mexico border, was created by ecologist Jack Dash and documentary photographer Luke Swenson. Email High Country News at [email protected] or submit a letter to the editor.

This coverage was supported by contributors to the High Country News Research Fund.

Note: A version of this story appeared in our print edition with errant information about the project’s connection to the University of Arizona; they are not affiliated. This story has been corrected. We also clarified the impact that climate change is having on elegant trogons (Trogon elegans) and updated captions that misidentified Stachys coccinea (scarlet betony) and Mentzelia montana (blazing star). 


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